[Cerrado] Redirect client side

Background of the issue:
I am trying to optimize the language redirection on my site enlace oculto using WPML. Initially, I used a client-side redirect, but it caused a one-second flash showing the wrong language before redirecting. To improve user experience, I switched to a server-side redirect based on the browser’s Accept-Language header, but I am concerned about potential SEO issues.

Symptoms:
There is a one-second flash showing the default language before the client-side redirect occurs.

Questions:
Is there any official method or best practice to optimize the client-side redirect and eliminate that initial flash?
Have you dealt with similar cases from other customers, and if so, how did they resolve it?
Would you recommend staying with the server-side redirect, or is there a better way to handle this situation with WPML?